Add a full stop after strings, since some voices use the existance of one to change intonation.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@20184 a1c6a512-1295-4272-9138-f99709370657

tools/voice.pl

@@ -140,6 +140,7 @@ sub correct_string {
                 }
                 case "festival" {
                     $string =~ s/\ba\b/ay/ig;
+                    $string =~ s/$/./;
                 }
             }
         }